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| Illustration 1 | g00669800 |
(1) The work tool joystick control (2) The interlock manifold valve (3) The accumulator (1A) Port 1 on the work tool joystick control (2A) Port 2 on the work tool joystick control (3A) Port 3 on the work tool joystick control (4A) Port 4 on the work tool joystick control (A) The pilot oil line from port 4 to the bank valve that tilts the work tool forward (B) The pilot oil line from port IP on the interlock manifold valve to port P on the work tool joystick control (C) Return oil from port T on the work tool joystick control to port RJ on the return manifold (D) Pilot oil from port 2 that tilts the work tool backward (E) Pilot oil from port 3 on the work tool joystick control to the bank valve that raises the lift cylinders (F) Pilot oil from port 1 on the work tool joystick control that lowers the lift cylinders (G) Pilot oil from port C2 on the interlock manifold valve for supplying the top hydraulic fitting on the high flow auxiliary circuit (H) Pilot oil from port A2 on the interlock manifold valve for supplying the bottom hydraulic fitting on the standard flow auxiliary circuit (I) Pilot oil from port A1 on the interlock manifold valve for supplying the top hydraulic fitting on the standard flow auxiliary circuit (J) Pilot oil that flows from port C1 on the interlock manifold valve for supplying the bottom hydraulic fitting on the high flow auxiliary circuit (K) Pilot oil flow from port "PS" on the front section of the hydrostatic piston pump to port "P1" on the interlock manifold valve (L) Pilot oil that flows from port PS on the rear section of the hydrostatic piston pump to port P2 on the interlock manifold valve (M) The drain oil line to port IM on the return manifold (N) The hydraulic oil line from port IP on the interlock manifold valve to the piston motors that release the parking brakes (O) The pilot oil line from port DP on the interlock manifold valve to port P on the hydrostatic joystick control (P) The drain oil line from port "T" on the hydrostatic joystick control that connects to the drain oil line from the interlock manifold valve (Q) The hydraulic oil line that flows from the ball valve to port T1 on the interlock manifold valve | |
The pilot hydraulic system consists of the following components: (1) work tool joystick control, (2) interlock manifold valve and (3) accumulator.
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| Illustration 2 | g00665671 |
For the 228 Skid Steer Loaders, when the engine is in operation, the hydraulic oil for the pilot hydraulic system flows from the hydraulic oil tank to the gear pump. The gear pump is located on the front of the front housing cover on the engine. From the gear pump, the oil flows to the fan drive motor. The oil powers the fan drive motor. The oil flows through the fan drive motor to the hydraulic oil filter. From the hydraulic oil filter, the oil flows to port "G1" (4) on the rear section of hydrostatic piston pump. Then, the oil flows to the speed sensing valve.
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| Illustration 3 | g00665680 |
The speed sensing valve is located in the rear section of the hydrostatic piston pump. The oil flows from the speed sensing valve to port "G" (5). At port "G", the oil flows through tube (6) to the front section of the hydrostatic piston pump. The tube enters the front section of the hydrostatic piston pump at port "G" (7). The oil flows through internal passages in the front section of the hydrostatic piston pump to port "PS" (8).
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| Illustration 4 | g00665683 |
From port "PS" (8), the oil flows to port "P1" (9) on the interlock manifold. When the work tool solenoid is energized, the oil flows through the work tool solenoid. The oil flows from port "IP" (10) to the work tool joystick control.
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| Illustration 5 | g00665757 |
On the 248 Skid Steer Loader, the oil for the pilot valve (joystick) that controls the motion of the work tools starts in the tank. Oil flows from the tank to the gear pump. When the engine is in operation, the oil flows from the gear pump to the fan drive motor. The oil flows from the fan drive motor to the pressure switch for the engine cut off circuit. From the pressure switch for the engine cut off circuit, the oil flows to the hydraulic oil filter. From the hydraulic oil filter, the oil flows to port "G1" (11) on the rear section of the hydrostatic piston pump. From port "G1", the oil flows to the speed sensing valve.
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| Illustration 6 | g00665765 |
The speed sensing valve is located in the rear section of the hydrostatic piston pump. The oil flows from the speed sensing valve to port "G" (15). At port "G", the oil flows through tube (16) to the front section of the hydrostatic piston pump. The tube enters the front section of the hydrostatic piston pump at port "G" (17). The oil flows through internal passages in the front section of the hydrostatic piston pump to port "PS" (18).
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| Illustration 7 | g00665769 |
From port "PS", the oil flows to port "P1" (19) on the interlock manifold. When the work tool solenoid is energized, the oil flows through the work tool solenoid. The oil flows from port "IP" (20) to the work tool joystick control.
The gear pump regulates the pilot system oil. When the speed of the gear pump increases, the pressure in the pilot system increases. The flow rate at the speed sensing valve increases. The increase in the flow rate at the speed sensing valve increases the pilot system pressure. When the speed of the gear pump decreases, the pressure in the pilot system decreases.
Refer to the System Operation, RENR2888, "Piston Pump (Hydrostatic)" for more information on the piston pump (hydrostatic).
Interlock Manifold Valve
The interlock manifold valve contains all of the solenoid valves that control the flow of pilot oil for the following systems: work tool controls, travel controls and auxiliary controls (if equipped).
In the interlocking manifold valve, the hydraulic oil flows into port "P1" in illustration 1. The oil flows to the solenoid relief valve for the auxiliary circuit. The flow of oil is blocked. Then, the oil flows through a check valve and the oil splits into four branches.
The first branch flows to the solenoid for the work tool joystick control. The second branch flows to the auxiliary circuit modulating valves (if equipped). The third branch flows to the solenoid for the high flow auxiliary circuit. The fourth branch flows to the accumulator.
Refer to the System Operation, RENR2888, "Interlock Manifold Valve" for more information on the interlock manifold valve.
Accumulator
The accumulator (3) in illustration 1 is mounted on the front of the interlock manifold valve (2). The accumulator (3) provides a limited amount of pilot oil after the engine is shut OFF. The oil capacity of the accumulator is 0.32 L (0.34 qt). The accumulator is charged to 900 kPa (130 psi) with 30.0 cc (1.83 in3) of dry nitrogen.
Work Tool Joystick Control
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| Illustration 8 | g00572541 |
Work tool control pattern | |
The pilot oil flows from port "IP" on the interlock manifold valve to port "P" on the work tool joystick control in illustration 1. The work tool joystick control is located on the right side of the cab. The work tool joystick control controls the lift cylinders and the tilt cylinders through the bank valve.
The work tool joystick control functions in the following positions: (4) FLOAT (5) LOWER (6) HOLD (7) RAISE (8) TILT FORWARD (9) TILT BACK.
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| Illustration 9 | g00533744 |
(A) Pilot oil for tilting the work tool forward. (B) Pilot supply oil from the interlock manifold valve. (C) Return oil to the manifold. (D) Pilot oil for tilting the work tool backward. (E) Pilot oil for lowering the work tool. (F) Pilot oil for raising the work tool. | |
HOLD Position
When the work tool joystick control is in the HOLD position (6), hydraulic oil flows from port IP on the interlock manifold valve through line (B) to port "P". The flow of oil is blocked in the joystick. The pilot signal lines from the LIFT spool on the bank valve and the TILT spool on the bank valve drain through the joystick to port "T". The oil flows through port "T" to line (C). Line (C) drains to the tank.
The work tool joystick control will return to the HOLD position when the lever is released from the following positions: (5) LOWER, (7) RAISE, (8) TILT FORWARD and (9) TILT BACK .
When you select the FLOAT position (4), the work tool joystick control will remain in the FLOAT position.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
RAISE Position
Move the work tool joystick control to the RAISE position (7). Pilot supply oil flows through port "IP" on the interlock manifold. The oil flows through line (B) to port "P" on the work tool joystick control. Then, the oil flows through the joystick to port "1". From port "1", the oil flows to line (F). From line (F), the oil flows to the lift control valve spool in the bank valve.
For machines with the diverter valve (if equipped), the lift control valve spool is moved by the pilot oil. The hydraulic oil flows through the spool to the head end of the lift cylinders. The lift cylinders raise the work tool. The oil from the rod end of the lift cylinders drain to port "A" on the diverter valve (if equipped). From port "A", the oil flows through the diverter valve (if equipped) to port "B". Then, the oil flows to the lift control valve spool. The oil flows through the lift control valve spool to the tank.
For machines without the diverter valve (if equipped), the lift control valve spool is moved by the pilot oil. The hydraulic oil flows through the spool to the head end of the lift cylinders. The lift cylinders raise the work tool. The oil from the rod end of the lift cylinders drain through the lift control valve spool to the tank.
Refer to the System Operation, RENR2888, "Diverter Valve" for more information on the diverter valve (if equipped). Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
LOWER Position
Move the work tool joystick control to the LOWER position (5). Pilot supply oil flows through port "IP" on the interlock manifold through line (B). The oil flows through port "P" on the work tool joystick control. The oil flows through the work tool joystick control to port"3". Then, the oil flows to line (E). From line (E), the oil flows to the lift control valve spool in the bank valve.
For machines with the diverter valve (if equipped), pilot oil moves the lift control valve spool. The oil flows through the spool and to port "B" on the diverter valve (if equipped). From port "B", the oil flows through a relief valve port "A". Then, the oil flows to the rod end of the lift cylinders. The lift cylinders lower the work tool. Oil from the head end of the lift cylinders flows through the lift control valve spool to the tank.
For machines without the diverter valve (if equipped), the lift control valve spool is moved by the pilot oil. The oil flows through the spool to the rod end of the lift cylinder. The lift cylinders lower the work tool. Oil from the head end of the lift cylinders flows through the lift control valve spool to the tank.
Refer to the System Operation, RENR2888, "Diverter Valve" for more information on the diverter valve (if equipped). Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
FLOAT Position
When the work tool joystick control is in the FLOAT position (4), the work tool joystick control will hold the FLOAT position. The work tool joystick control has a detent in the FLOAT position. The detent allows the work tool joystick control to remain in the FLOAT position until the work tool joystick control is removed from the detent.
The pilot supply oil flows through port "IP" on the interlock manifold through line (B) to port "P" on the work tool joystick control. The oil flows through the work tool joystick control to port "3". Then, the oil flows through port "3" to line (E). From line (E), the oil flows to the lift control valve spool in the bank valve.
For machines with the diverter valve, pilot oil moves the lift control valve spool. The supply oil is blocked at the spool. The hydraulic oil in the head end of the lift cylinders drains through the spool to the tank. Hydraulic oil in the rod end of the lift cylinders flow to port "A" on the diverter valve. Then, the oil flows through the diverter valve and exits at port "B". The oil flows from port "B" to the lift control valve spool. Then, the oil flows through the lift control valve spool to the tank. The lift cylinders retract. The lift cylinders lower the work tool. The work tool will follow the contour of the ground as the machine moves.
For machines without the diverter valve (if equipped), the lift control valve spool is moved by the pilot oil. The supply oil is blocked at the spool. The hydraulic oil in the head end of the lift cylinders drains through the spool to the tank. Hydraulic oil in the rod end of the lift cylinders flow to the lift control valve spool. Then, the oil flows through the lift control valve spool to the tank. The lift cylinders retract. The lift cylinders lower the work tool. The work tool will follow the contour of the ground as the machine moves.
Refer to the System Operation, RENR2888, "Diverter Valve" for more information on the diverter valve (if equipped). Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
TILT FORWARD Position
When you select the TILT FORWARD position (8), pilot oil flows from the interlock manifold valve port "IP" through line (B) to port "P" on the work tool joystick control. The hydraulic oil flows through the work tool joystick control to port "4". The hydraulic oil flows through port "4" to line (A). From line (A), the oil flows to the tilt control valve spool in the bank valve.
The tilt control valve spool is moved by the pilot oil. The hydraulic oil flows through the tilt control valve spool. The oil flows toward the tilt cylinders and branches. One branch flows to port "D" in the diverter valve (if equipped). An internal check valve blocks the flow of the hydraulic oil.
The second branch flows to the head end of the tilt cylinders. The cylinder rods extend. The work tool tilts forward. Oil from the rod end of the tilt cylinders flow toward the tilt control valve spool and branches. One branch flows to port "C" on the diverter valve (if equipped). The flow is blocked. The second branch flows to the tilt control valve spool and the oil is directed to the tank.
Refer to the System Operation, RENR2888, "Diverter Valve" for more information on the diverter valve (if equipped). Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
TILT BACK Position
Move the work tool joystick control to the TILT BACK position (9). The pilot hydraulic oil flows through port "IP" on the interlock manifold to port "P" (B) on the work tool joystick control. Then, the oil flows through the work tool joystick control to port "2" and line (D). From line (D), the oil flows to the tilt control valve spool in the bank valve.
The tilt control valve spool is moved by the pilot oil. The oil flows through the tilt control valve spool toward the rod end of the tilt cylinders. The hydraulic oil line divides into two branches. The first branch flows to port C on the diverter valve (if equipped). The flow of oil is blocked. Then, the oil flows to the rod end of the tilt cylinder. The oil from the head end of the tilt cylinders flows to the tilt control valve spool. From the tilt control valve spool, the oil flows to the tank. The rods retract and the work tool tilts backward.
Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Work Tool Control" for more information on the work tool joystick control. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Work Tool Control" for more information on the work tool joystick control.
Auxiliary Position 1
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| Illustration 10 | g00669545 |
Press the left side of the switch for the auxiliary circuit (10). The solenoid for the auxiliary circuit on the interlock manifold energizes. Pilot oil flows through port "A2" on the interlock manifold. The oil flows through line (H) in illustration 1. Then, the oil flows to the auxiliary control valve spool in the bank valve.
The auxiliary control valve spool shifts. Hydraulic oil flows through the auxiliary control valve spool and out of the bottom auxiliary line. The top auxiliary line is the return line. The oil in the return line flows to the auxiliary control valve spool and to the tank.
Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Auxiliary Hydraulic Control" for more information on the auxiliary hydraulic circuit. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, " Auxiliary Hydraulic Control" for more information on the auxiliary hydraulic circuit.
Auxiliary Position 2
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| Illustration 11 | g00669547 |
Press the right side of the switch for the auxiliary circuit (11). On the interlock manifold, pilot oil flows through port "A1" to line (I) in illustration 1. From line (I), the oil flows to the auxiliary control valve spool in the bank valve.
The auxiliary control valve spool shifts. The oil flows through the auxiliary control valve spool and to the top auxiliary line. The bottom auxiliary line is the return line. The oil in the return line flows to the auxiliary control valve spool and to the tank.
Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Auxiliary Hydraulic Control" for more information on the auxiliary hydraulic circuit. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, " Auxiliary Hydraulic Control" for more information on the auxiliary hydraulic circuit.
Position 1 for the High Flow Auxiliary Circuit
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| Illustration 12 | g00670150 |
The high flow auxiliary circuit is controlled by the switch (12). The switch allows the three-position, four-way solenoid on the interlock manifold to activate.
The left side of the switch is "H2". Pilot oil flows through port "C2" on the interlock manifold and through a 1 mm (0.04 inch) orifice. Then, the pilot oil flows through line (G) in illustration 1 to the bank valve.
The pilot oil moves the spool. Hydraulic oil flows through the spool and to the top fitting for the high flow auxiliary circuit. The bottom fitting for the high flow auxiliary circuit acts as the return line. The oil flows through the bottom fitting to the spool. Then, the oil flows through the spool to the tank.
Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "High Flow Control" for more information on the high flow auxiliary hydraulic circuit. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, " High Flow Control" for more information on the high flow auxiliary hydraulic circuit.
Position 2 for the High Flow Auxiliary Circuit
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| Illustration 13 | g00701017 |
The high flow auxiliary circuit is controlled by the switch (12). The switch allows the three-position, four-way solenoid on the interlock manifold to be activated.
The right side of the switch is "H1". Pilot oil flows through port "C1" on the interlock manifold and through a 1 mm (0.04 inch) orifice. Then, the pilot oil flows through line (J) in illustration 1 to the bank valve.
The pilot oil moves the spool. Hydraulic oil flows through the spool to the bottom fitting for the high flow auxiliary circuit. The top fitting for the high flow auxiliary circuit acts as the return line. The oil flows through the top fitting to the spool. Then, the oil flows through the spool and to the tank.
Refer to the System Operation, RENR2888, "Bank Valve" for more information on the bank valve.
On the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "High Flow Control" for more information on the high flow auxiliary circuit. On the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, " High Flow Control" for more information on the high flow auxiliary circuit.